Rotary drill pipe



Dec. 1924- I 1,517,428

. H G. JAHRAUS I ROTARY DRILL PIPE Filed Dec. 5. 1923 IN VEN TOR.

, f" {f/WATTORNEY M f /7 BY jug STATES PATENTOFFICE.

HENRY G-. J'AIHRAUS, LOS ANGELES, CALIFORNIA, ASSIGNOR OF ONE-HALF TOWILLIAM R. MITCHELL, 0]? LOS ANGELES, CALIFORNIA.

ROTARY DRILL PIPE.

A Application filed December 5, 1923. Serial No. 678,657.

To all whom it may concern. plings of 5.256 inches outside diameter inno Be it known that I, HENRY G. JAHRAUS, smaller than 8% inch poundcasing of a citizen of the United States, residingat 7.825 inchesinside-diameter.

Los Angelesfln the county of Los Angeles Heretofore, in running theordinary type 5 and State of California, have invented a new ofdrill-pipe in an open hole, the couplings to and useful Rotary DrillPipe, of which the break through the mud wall and where this followingis a specification. occurs in sand or other soft'stratas the sand Thisinvention relates to rotary drill-pipe is very liable to run into thehole and cause and is particularly directed to an improved largecavities leading to a crooked hole and I0 type of drill-pipeespeciallyadaptable .for much difiiculty in subsequently inserting a usein drilling deep wells by the rotary syscasing. tem of drilling. 1Therefore, it would bedesirable to pro-3 Drill-pipe of the character nowin general duce a drill-pipe having couplings of the use compriseslengths of pipe of uniform disame outside diameter as the drill-pipesec- 15 ameter threaded at both ends and joined tions, permitting alarger size drill pipe to by standard couplings and at every second'orbe run in a given size of casing, that is, tothird length throughout thelength of the permit a four inch drill-pipe to be run in a drill-pipestring there is provided what is smaller than 8% inch 40 pound casing. Auniversally knownas a Hughes tool joint drill-pipe of this characterwould beespe- 20 andof the general character-illustrated and ciallyadvantageous by reason of the case described in United States LettersPatent with which it could be lowered 'or pulled I #964,353, issued toM. H. Whittier, July, and would eliminate much of the danger of 12,1910, the purposes and advantages of becoming frozen in the well bore,such such tool-joints being so well known as to freezing being in largemeasure due to the 5 require no detailed description herein. standardcouplings scraping the mud from With such standard character of drillthewalls of the well bore. pipe various disadvantages are encountered It istherefore an object of the present inand accidents leading to expensiveand tevention to provide an improved type of 'drill-, f 'dious fishingjobs are of frequent occurrence, pipe in which relative vibration of thecom- 0 such fishing jobs being often due to a twistponent parts iseliminated. 1 1, off at the pipe threads and couplings. A A furtherobject is to provide a drill-pipe twist-ofi' of this nature may be dueto one comprising a plurality of pipe sections or more of severalcauses, among which may joined in a manner to withstand a greater bementioned, subjecting the pipe to a greatrotary strain than standardthreaded pipe 35 er rotary strain than the pipe threads will andcouplings. withstand, bending strains occasioned '-by .Another object isto form the couplings crooked holes, and relative vibration of, the andp'pe ends so as to provide greater stapipe lengths and couplingsinducing a crysbility against bending strains. tallization of the pipeends. In the greater Another object is to provide a drill-pipe number-oftwist-off, the break'occurs at composed of pipe sections and connecting95 the last threads on the pipe and immediately couplings all of uniformoutside diameter. adjacent the edge of a coupling. the pipe be- Afurther object is to provide a drilling' weakened by the cutting of thethreads. pipe composed of threaded p'ipe sections and With standarddrill-pipe of uniform di-w threaded connecting couplings having co-en:

5 ameter the couplings are considerably gaging tapered surfacesrelieving the greater in outside diameter than are the pipsahreads of amajor portion of the rotary lengths and as such drill-pipe must operatestrains. j within well casing containing mud-water in A still furtherobject is to provide adril1- circulation it -follows that the outsidedipipe'of the above character-,-'which has a ameter of such couplingsmust be considergreater resistance againstbending, twisting,

' vably smaller than the, insidediameter of and longitudinal strains,than standard the casing to allow suflicient clearance for threaded pipeand couplings, and in'whicha freecirculation of the mud-water. Incrystallization of the component parts has deep well drilling it isconsidered good pracbeen reduced to a minimum.

ties to run four inch drill-pipe'having cou- Another: object is toprovide a drill-pipe 1 of the above character, including one or moretool-joints and in which the adjacent pipe sections are connected to therespective pin and box members of the tool-joint in the same manner asthe pipe sections are connected to theipipe couplings.

Various other objects and advantages will be more fully apparent fromthe following description of the accompanying drawings which form a partof this disclosure, and which illustrate a preferred form of embodimentof the invention.

Of the drawings:

Fig. 1 is a longitudinal section through a portion of a drill-pipestring.

Fig. 2 is a section on line 22 of Fig. 1, and Fig. 3 is a section online 3 3 of Fig. 1.

Fi 4 is a semi-diagrammatic section showing the tapered portions of apipe end and the couplings. X

Referring to the drawings, 1 designates pipe sections joined together bycouplings -2, and 3, 4 designates'the pin and box members respectivelyof a tool-joint which may 'be inserted between the pipe sections atdesired intervals throughout the length of the drill-pipe line. i

It will be noted that the pipe sections 1 have their ends'reduced indiameter and formed to provide smooth tapered or cone portions 5terminating -with externally screw-threaded end portions 6.

Preferably the pipe section ends are upset to secure greater wallthickness so as to provide an exceptionally strong and durableconstruction, this being accomplished without reducing the internal boreto a diameter smaller than the bore of standard drill collars used in.connection with rotary drill-pipe.

By so reducing the diameter of the ends of the pipe sections it becomespossible to make the coupling 2 no greater in diameter than the normaldiameter of the pipe sections andat the same time to make the couplingof sufficient wall thickness to withstand all strains to which it may besubjected.

The bore of the coupling 2 is formed to correspond with the ends of thepipe sections, that is, said bore is tapered inwardly from its ends toprovide cone sockets 7 to receive the respective tapered or coneportions 5 of adjacent pipe sections, and is internally screw-threadedat 8 between the tapered portions to receive the externallyscrew-threaded end portions of the respective pipe ends, thescrew-threaded portions being straight, or at least of such character asto allow the tapered portions to tightly coengage before the threadedportions bind to prevent such coengagement.

With this construction the screw-threaded portions exert a longitudinalpull drawing the tapered cone ends of the pipe sections into the taperedcone sockets of the couplings, the coengaging tapered surfacesfunctioning much in the same manner as those of a taper-shank twistdrill or tapered lathe-centers and taking a major portion of the rotaryor twisting strains, leaving the screw-threaded portions a main functionof exerting a longitudinal pull maintaining the tapered surfaces tightlyengaged.

While tapered cone and socket surfaces of any appreciable length willmore or less resist rotary or twisting strains it will be obvious thatin a drill-pipe for drilling deep wells, the degree of taper should morenearly approach that used on heavy duty twist drills and lathe centers,while at the same time such taper should be such as to permit adisconnection of the pipe sections with the power available withstandard rotary drill rigs, and while the degree of taper illustrated isbelieved to be thoroughly practical, that to be used in actual practicewill be determined more or less by experience under various conditions.

Further as the tapered cones and sockets also serve the purpose ofstrengthening the connection against bending strains, it will be statedthat the length of suclntapered cones and sockets in relation to theangle of the taper and their diameter is of importance. With referenceto Fig. 4 and considering only the tapered portions (disregarding thethreaded portions) it will be pointed out that if the tapered surfacesextended only from line a of greatest circumference to the line b andwith the coupling stationary and a bending force applied to the pipesection in the direction sect the wall of the coupling, therefore insuch instance the tapered portions of the pipe section and couplingwould offer no resistance to such bending action and would place theentire burden upon the threaded portions.

In the present invention the tapered portions are of a length to bringtheir lower ends considerably outside of the arc f so that with anybending strains tending to rock the pipe section about the point d, orany similar point on the major circumference of the coupling taper, theline of force exerted by the point g, or any similar point on the minorcircumference of the taper of the pipe section, along the arch, willintersect and be resisted by the wall of the coupling. In describingthis it may be said that the taper of the coupling is so formed that thedistance :0 from a given point (i on its larger circumference a to thenearest diametrically opposite portion 6 is less than the distance 3from said point 12 to a given point 9 on the smaller circumference is ofsaid taper.

The tool-joint incorporated in a drillpipe line of this charactercomprises the pin section 3 having the usual tapered externallyscrew-threaded pin L0, and the box section 4 having the usual taperedinternally screw-threaded box 11 to receive the pin.

The opposite ends of both the pin and the of approximately the sameexternal di-' ameter as are the pipe sections, (this being done only toshow how these diameters may be reduced if so desired, it is recognizedthat in ordinary oil field practice and using the more or less standardtypes of elevators, it is desirable that the tool-joint members and insome cases also the couplings, be

slightly larger in diameter than the pipe sections so as to provide ashoulder for engagement by the elevators, therefore, it is to beunderstood that the tool-jointmembers and couplings herein may beslightly increased in diameter for this purpose, without departing fromthe spirit of the invention which in its major aspect relates to thetype of joint or connection employed.

The above described construction provides a drill-pipe line .ofexceptional strength and durability and which has many advantages indeep well drilling, over the type now in general use, and while thespecific form of embodiment herein illustrated and described having abore tapered inwardly from its outer end and having an internallyscrewthreaded portionbeyond the taper, said tapered bore being formed sothat the distance from a given point on its larger circumference to thenearest diametrically opposite portion of itstapered surface is lessthan "the distance from said point to a diametrically opposite point onthe smaller circumference of the taper, and an adjacent member formed toprovide a tapered portion ter- 'm-ina-ting with an externallyscrew-threaded end portion, the tapered and threaded portions of saidadjacent member corresponding with and adapted to engage within the:likeportions of the first named'member'.

2. In a rotary drill-pipe, a coupling having a bore tapered inwardlyfrom its outer end and having a straight internally screw threadedportion beyond the taper, said tapered bore being formed so that thedistance from a given point on its larger circumference to the nearestdiametrically .opposite portion of. its tapered-surface is less than thedistance from said point to a diametrically opposite point on thesmaller circumference of the taper, and a pipe section having an endreduced in diameter and formed to provide a smooth tapered portionterminating with a straight externally screw-threaded end portion oflesser diameterthan the normal diameter of the pipe section, the taperedand threaded portion of the pipe section corresponding with and adaptedto engage within the like portions of the coupling bore.

3. A rotary drill-pipe including a plurality of pipe sections and anintermediate cennecting coupling, the end of each pipe section beingreduced in diameter and formed to provide a smooth taperedportion-terminating' with a straight externally screwthreaded endportion of lesser diameter than the normal diameter of the section, andthe coupling having a bore tapered inwardly from its opposite ends andinternally screwthreadedbetween the tapered portions with thetapered'and threaded portions of the coupling bore corresponding tothose of the pipe sections, whereby said sections may be screwed intothe respective ends of the bore to engage the co-operating taperedsurfaces.

4.' A rotary drill-pipe including a coupling having a bore taperedinwardly from its opposite ends and internally screwthreaded betweenthetapered portions,,each tapered portion being formed so that thedistance from a given point on its lar er circumference to the nearestdiametrica y opposite portion of its tapered surface is less than thedistance from said point to a diametrically opposite point on thesmaller circumference of the taper, and pipe sections each having an endreduced in diameter and formed to provide a smooth tapered portionterminating .with a straight externally screwthreaded end portion oflesser diameter than the normal diameter of said section, the taperedandthreaded portions of the pipe sections corresponding with those ofthe coupling whereby said sections may be screwed into the respectiveends of the bore to engage the co-operating tapered surfaces.-

5. In a rotary drill-pipe, a plurality of pipe sections each having anend reduced in diameter and formed to provide a smooth tapered portionterminating with a straight externally screw-threaded end portion, and

a tool joint comprising a tubular box member having a tapered internallyscrewthread'ed socket at one end and a tubularpin member having atapered externally screwthreaded pin at one end adapted to engage withinthe threaded box of the box member, the opposite ends of the box and thepin members each having their bores tapered inwardly and internallyscrew-threaded beyond said tapered portions to correspond to the taperedand screw-threaded ends of the pipe sections, whereby, the pipe sectionsmay be screwed into the respective 'tool-j oint members to engage theco-operating tapered surfaces and the tool-joint tapered screwthreadedpin may be screwed into the tooljoint tapered screw-threaded box.

6. In. a rotary drill-pipe, a pipe section having an end upset toprovide a wall of increased thickness and reduced in diameter to form asmooth tapered portion terminating with a straight externallyscrew-threaded end portion of lesser diameter than the normal diameterof the section, and a coupling having a bore tapered inwardly from itsouter end and internally screw-threaded beyond the taper to accommodatethe tapered and threaded end of the pipe section.

7 A rotary drill-pipe connection comprising a tubular box member havinga screwthreaded socket at one end, and a tubular pin member having ascrew-threaded pin at one end adapted to engage within the socket of thebox member, the opposite ends of the box and pin members each havingtheir respective bore tapered inwardly and internally screw-threadedbeyond said tapered portion, the tapered portion of the bore of eachmember being formed so that the distance from a given point on itslarger circumference to the nearest diametrically opposite portion ofits tapered surface is less than the distance from said point to adiametrically opposite point on the smaller circonference of the taper.

Signed at Los Angeles, California, this 24th day of November, 1923.

HENRY G. JAHRAUS.

